Creating a new outdoor interior?

[silaent]

Hey guys and gals,

 

For a while I've been trying to get the hang of the creation kit. I've built about a dozen player homes and honestly I take pride in it because it's about as fun as playing the actual game. However, I got an idea for a new home I want to create but I'm not quite sure how to go about it. Basically, my idea is to put a Load door into Tamriel somewhere and have it linked to a cell separate from Skryim (as an interior is) but have all the outdoor aspects (sky, actual land, etc.) I only have experience with creating interiors and homes outside and I don't want to go rearranging the actual landscape because things tend to get messy. I want to have a pretty small valley surrounded by mountains that act as walls, with the load door being the only exit and tie to the main world. However, map-wise, I want it to appear to still be in the same location (I don't want it to seem like that cave entrance just teleported me to another world). Is it possible to simply copy an existing cell and begin construction as if it were an Interior? How do I go about setting up the new cell to appear in the same location that the cave entrance was? Thanks for your help!